Birds are tricky critters to keep out of a preferred buffet of ripening crops, affirms wildlife biologist Dr. George Linz. And he ought to know. Linz has spent more than 30 years studying their behavior, primarily working on blackbird ecology and developing methods of reducing damage. His research team has developed, for example, the use of glyphosate for controlling cattails used by roosting blackbirds.

During his long career with USDA-APHIS-Wildlife Services, Linz has seen many bird repellent products come and go, personally conducting or being otherwise involved in experiments with many of them. Chemical bird repellents have been on the market for several years. Two commonly used registered bird repellent products on sunflower are Bird Shield™ and Flock Buster™. Both consist of natural ingredients, with proven results repelling birds in many different environments.

The challenge with any repellent, according to Linz, is applying sufficient product to affect the bird’s feeding behavior without breaking the bank. Rain can reduce the longevity of the product, and getting the product on the face of the sunflower head is a challenge.

Linz emphasizes that USDA and North Dakota State University do not promote one product over another. They simply go by their findings. “We don’t advocate a specific product, but instead report our data in the scientific literature for other researchers to evaluate. It’s pretty simple. Did it work or not,” Linz explains.

A team of researchers from USDA-Wildlife Services and NDSU has spent the 2012 growing season working with two repellents – Avian Control™ and Avipel™. The former is already EPA-approved and labeled for sunflower; the latter is not and is still in the research phase.

New to Sunflower

This spring, Steve Stone of Avian Enterprises (a division of Stone Soap Company) contacted Linz regarding his product, Avian Control. Linz, in turn, contacted the National Sunflower Association to discuss research potential with the company’s bird repellent for use on sunflower.

Stone’s company specializes in soap and deodorizers. One might question how a soap company would have any idea how to get rid of pesky birds. It all began with a Chicago-area landfill management company with bird problems. As a customer purchasing deodorizers from Stone Soap Company, they inquired about a solution to the bird issue. This precipitated the Michigan-based firm to formulate a bird repellent for its customer. It was unchartered waters for the soap company that unexpectedly produced a very effective solution to the landfill’s bird problems.

The solution – Avian Control – contains the primary ingredient of methyl anthranilate (MA). MA has been has been known as an effective bird aversion chemical since the 1960s. Using this naturally occurring compound that is found in flowers and grapes, MA works as a repellent by stimulating the nerves in the bird’s beak, eyes and throat. Although most animals have these nerves, only birds react to MA. Other bird repellents on the market (e.g., Bird Shield) contain this ingredient as well. But Stone Soap’s formula has an added ingredient that enhances the chemistry of the product to make MA more effective. Essentially, the “secret” ingredient gives an added boost to MA that no other product on the market provides.

One negative of MA is that it is biodegradable over time. To counter this, Avian Control added an inert ingredient called propylene glycol (a preservative also used in the food and cosmetic industry), giving the product more sustainable lasting effects.

Birds are creatures of habit, so any good repellent focuses on behavior modification. Stone emphasizes that early application is key to training the birds to go elsewhere. “If they have learned that a buffet has been set up for them and it was delicious one day, then not the next, it takes them a while to ‘get it’ that it won’t taste good tomorrow either,” he explains. “So it takes a while to modify their behavior.”

This EPA-approved, non-lethal repellent discourages birds from congregating in the field and eating the seeds. The product also has been found to possess an ultraviolet component to which birds are sensitive. The combination of the chemical ingredients in Avian Control is creating the ultraviolet footprint that only birds can see and seem to want to avoid. The idea is that the birds are able to detect a color that would signal a response.

It’s approved for sunflower, sweet corn and several fruits. Until this year, Avian Control has been used on blueberries and cherries with much success. This prompted Stone to seek out research projects on sunflower.

Testing Avian Control on ’Flowers

Stone says there are various Avian Control studies going on for fruit crops and sweet corn as well as some research in South Dakota with soybeans to deter Canada geese from eating emerging seedlings. Prior to Stone contacting Linz, however, nothing had been done with sunflower. He agreed to supply the chemical at no charge, if Linz and his group would agree to help coordinate the sunflower studies for the 2012 growing season.

Sunflower presents some very unique issues not present in fruit crops. One is the stature of the plant; another is the range of coverage required on a multi-acre field for efficacy. In other words, how do you spray a plant that’s over five feet tall (in most cases), and how do you get the chemical on the face of the sunflower when the head faces downward. That’s where Linz and his expertise and experience applying various repellents come into play.

“How do we get the chemical on the seed and when do we spray it?” Stone questions. “Longevity is the key to making the product effective when sunflower is vulnerable to birds.”

Linz arranged for 10 growers from across North Dakota to spray approximately 50 acres each. The formulation is two quarts of Avian Control per five gallons of water was sprayed with aerial application in late August/early September. Even though it’s an experimental project, because the product is an EPA-approved chemical, the crop did not need to be destroyed and the product is available on the marketplace. It’s not often that research is done with an already-approved and -labeled product.

Mike Christenson, sunflower grower from Rugby, N.D., says he’s impressed with Avian Control. He traditionally grows a couple hundred acres of oil sunflower each year, and there’s always blackbird pressure in his area of north central North Dakota.

At the time of Christenson’s observations, the chemical had been sprayed nine days prior, in early September. “We sprayed a little over half of this 80-acre field, and it had a lot of blackbirds,” he recounts. “It took maybe until the second day or so, and then I’d watch the flocks of birds come down toward the field — and then, instead of landing, they’d swoop off into my neighbor’s corn field. It seems to have worked in this area.”

Christenson has also employed other means of harassing the birds, such as shotguns; but he says the chemical has seemed to make quite a difference in the field. At a week or two prior to harvest, he says he didn’t see a bird anywhere on a visit to the field.

Coleharbor, N.D., grower Tim Eslinger says the group of birds that was in his field prior to the Avian Control spray also was gone by early October. The treated 50 acres were in what he would consider a “problem area” prone to blackbird activity. Eslinger hadn’t grown sunflower in over 20 years, but brought it back as another rotational option. “From what I’ve seen, it seems to have worked. The birds have moved out,” he notes.

While early observations are positive, Linz says there’s more work to be done. “I haven’t looked at my numbers yet, but we are hearing positive results from our field staff in the areas that they are watching,” he states. “We can’t say anything definitive yet. We need a much larger sample than what we had this year. Five hundred acres spread across 10 different fields is not really enough in the world of birds. It’s so complex in the way they move between fields and from confection to oil sunflower and also early ripening corn.”

Linz is planning to report the findings from the Avian Control study at the annual National Sunflower Association Research Forum in Fargo in January. He will be interviewing each grower involved in the experiment as well as the field staff, getting their opinions and observations along with his numbers on damage assessment.

Ongoing Work With Anthraquinone

Another repellent project — one that has involved multiple USDA and NDSU researchers — is studying a chemical known as Anthraquinone (AQ). Available since the 1950s, AQ is gaining momentum as a blackbird repellent.

“It’s the only product we’ve tested in the laboratory and enclosures that consistently repels birds,” Linz says. He knows that is a bold statement, but he’s speaking from results.

Linz communicates regularly with company reps to see what it’s going to take to get the product on the market. The company that holds the patent for Avipel (with AQ as the active ingredient) is small, and the marketing process is costly and lengthy.

Even though the chemical has been around for a long time, it is not approved for use on sunflower. But because of its strong and consistent efficacy in trials, Linz says he wants to follow the research to its end, wherever and whenever that might lead.

A multi-year USDA study has been evaluating Avipel and its efficacy as a bird repellent on seed crops such as sunflower, corn and rice since 2009. That year, the product received a Section 18 label from EPA. It is an approved corn seed treatment in eight states, including four major sunflower-producing states (Minnesota, North Dakota, South Dakota and Texas). It is primarily used for defense against pheasants that eat the emerging corn. It’s also a rice seed treatment.

In 2009, after preliminary lab work was conducted, NSA funded research on ripening confection sunflower. This work included field research with bird enclosures. More field work with bird enclosures was conducted in 2010 — but this time on oilseed sunflower. Each year took into account different rates and modes of application. These crop-destruct studies are limited to 10 acres or less.

No work was conducted in 2011. This season, Linz and crew conducted field trials in small plots in an open environment. In cooperation with a grower near Turtle Lake, N.D. (central part of the state), Avipel was applied with a ground sprayer on roughly seven acres of oilseed sunflower in three different locations. A preliminary spray was done on August 17 (2 qts/acre) and another on August 31 (0.5 gal/ac) at the R-6 stage of development. Both applications were done by a high boy ground rig. Linz and staff then clipped heads in order to conduct residue levels on the bracts and seeds. They also took bird damage measurements throughout the process. Lab work will continue with the 2012 samples.

The goal is to acquire a special experimental use permit from the EPA in 2014 and to work toward field study on a large commercial scale on multiple acres. “It’s a long process,” admits Linz. “But we talk to so many growers who simply tell us they just need a little help with the birds. That’s what we’re trying to accomplish.”

The point is that management options do exist, and more are emerging all the time. The key is to find a repellent the grower can count on with consistent results. Linz adds, “We’re looking at all the options out there to help the farmer. The grower works too hard to get his profit taken from him this close to harvest.”